Getting
great bokeh in a lens like this isn't likely to happen. This lens is
designed for sharpness, fast focus speed, reasonable distortion, no
ghosts, VR and a huge zoom range. it uses aspheric elements which mess
up bokeh, and VR also does weird things to in areas not intended to
be in focus.

If bokeh is critical
you know who you are. You probably want a DC or
other f/2.8 or faster lens designed with an eye towards bokeh. Bokeh
isn't related to aperture or your diaphragm; it's just that those particular
lenses tend to have better bokeh.

Of course you
can blur backgrounds in Photoshop. It's a pain to select the background
and it's tough to get the transitions between blurred background and
foreground to look natural. If all I did were headshots I'd prefer
an 80-200 2.8 AF-D instead for not much
more expense.

This is a tight
crop (only about a linear third of the image) from a shot made at 200
mm at f/5.6. Note the busy background full of donut-looking things.
Good bokeh would leave the background soft, fuzzy and not distracting
like this. Typical bokeh would just be full of disks, not donuts. Great
bokeh would have a completely soft and smooth background.

Example
of Bad Bokeh. The blurs of the out-of-focus twigs still have
sharp edges. Good bokeh would have soft-edged blurs.